The present invention relates to a method and apparatus for winding cooling coils with a plurality of successive superimposed layers of rectangular configuration with stamped corners.
Cooling coils of rectangular configuration are used for refrigeration appliances, especially deep freezer chests. The cooling coils are delivered in finished form to the manufacturer of the refrigeration appliance for assembly. The manufacture of cooling coils of the aforementioned shape has up to now been carried out in a plurality of separate manufacturing steps. The tubes are straightened in a straightening machine and thereafter cut to a predetermined length. Subsequently thereto the thus-prepared tubes are bent into coils with a semi- or fully-automatic winding-up machine. To finish form the bent corners of the coil it is customary to place the pre-bent tube coil between the tools of a hydraulic press to simultaneously form a set of corners by stamping. Thereby, it is usually necessary to place the coil four times in turned positions into the press, i.e., according to the number of corners of the coil. The up to now used method comprises, therefore, three operating steps, i.e., tube straightening, tube bending, and stamping of the corners, whereby the last step usually requires placing the bent tube four times into the press.
While, due to the automatic bending of the coil, a simplification of this bending process is obtained, the known process has still the disadvantage that the bent coil has to be subsequently transported and placed into a press which complicates the manufacture and leads often to rejects.